Alloy



Patented Aug. 8, 1933 PATENT OFFICE) ALLOY Robert H. Leach, Fairfield, Cnn., assignor to Handy & Harman, New York, N. Y., a Corporation of New York No Drawing. Application May 4, 1933 Serial No. 669,370

4 Claims.

This invention relates to alloys used for brazing and welding and is concerned more particularly with a novel quaternary alloy which has relatively low melting and flow points and which can be used with great facility in producing joints of high tensile strength.

The new alloy includes silver varying from 4% to 36%, copper varying from 55% to 80%, tin varying from 5% to 15%, and phosphorus varying from 2% to 6%, the range limits given being approximate. Specific examples of the new a1- loys may have approximate compositions as folows:

Per cent 1 Silver 4.0 Copper 78.1

Tin 13.4

Phosphorous 4.5

2. Silver 14,3 Copper 69.5 Tin 11.2

Phosphorus 5.0

3. Silver 14.4

Copper 70.4 Tin 11.4

Phosphorus 3.8

4. Silver 24.0

Copper 63.3 Tin 1- 9.5

Phosphorus 3.2

.5. Silver 36.0 Copper 54.5

Tin -r. 7.1 Phosphorus 2.4

ranging from 1 to 1 of each eutectic'to 1 of the.

silver-copper eutectic to 18 of the copper-tinphosphorus eutectic with such small variations as may be desirable to obtain the best combination of thermal and physical properties. The silver-copper eutectic contains approximately 72% silver and 28% copper, while the coppertin-phosphorus eutectic contains approximately ployed.

81% copper, 14.2% tin, and 4.8% phosphorus. Accordingly, in developing this new alloy, I have departed in some instances from this combination of the 'eutectics by varying the amounts of the ingredients. For example, in an alloy containing, silver 10%, copper 73.5%, tin 12.2%, and phosphorus 4.1%, which represents a combination of eutectics, it is possible to increase the copper to 75.7% and lower the phosphorus to 2.1%, the tin and silver remaining the same, Without changing the characteristics of the alloy so that it cannot be used for brazing purposes.

The alloys within the ranges specified have closely similar melting and flow points as, for example, the alloy given in example No. 1 above and containing 4% of silver has a melting point of 1130 F. and a flow point of 1230 F. whereas the alloy given in example No. 5 which contains 36% silver has a melting point of 1115 F. and a flow point of 1295 F. It will thus be apparent that the thermal properties can be kept within reasonably close limits over a considerable range of composition and allow the use of an alloy with low silver content for brazing or welding purposes in those cases where the better physical properties of the alloys with higher silver content are not necessary.

Substantially all the alloys having the compositions within the ranges mentioned can be hotrolled at 900 F. to 1000 F., and the ease with 85 which they can be rolled increases with the silver content. When used as a solder and without a flux, the alloys flow along the seam or through the joint to a substantial extent, and tensile strength tests of copper butt joints made with the solders show average strengths in pounds per square inch ranging from 19,000 to 29,100. The butt joints thus made can be bent to an angle of 180 and hammered flat without cracking.

By reason of the relatively low temperatures at J which the new alloys can be used for welding and brazing purposes and of the strong joints which it produces, they can be used to great advantage in the manufacture of electrical machinery, for example, in the soldering of transformer leads. Also, since little or no flux is required, they may be used with excellent results in operations in which resistance heating is emfrom about 55% to about 80%, tin varying from about 5% to about 15%, and phosphorous varying from about 2% to about 6%.

4. An alloy which consists of silver varying from about 24% to about 36%, copper varying from about 55% to about 64%, tin varying from about 7% to about 11%, and phosphorus varying from about 2% to about 3.5%.

ROBERT H. LEACH. 

